PHY10L-E106

Gicale, Patrick Emmanuel T. PHY10L – B5 Prof. Rayda B. Gammag

DOP: December 4, 2015 DOS: December 11, 2015

Guide Questions: 1. When the radius and mass are held constant, what do you expect to happen to the centripetal force if the frequency of rotation is increased? - Since the equation of centripetal force is (F = m4π2ƒ2 r), wherein ƒ is the frequency of rotation, and the radius and mass are constant, it will still imply that centripetal force will increase. 2. What will happen if the centripetal force apparatus was set up slightly off the horizontal? - It will affect the centripetal force because it will have an additional horizontal force since it is inclined which implies an increase to centripetal acceleration. Problems 1. A ball rotates in a horizontal circle at a constant speed of 10 m/s. What are the tensions in the upper and lower strings? The mass of the ball is 3kg.

2. What angle of a bank is necessary for a car to make it around a 130m curve at a speed of 60kph without relying on friction?

3. Determine the speed of the satellite orbiting at a height of 700 km above the Earth’s surface.

Remarks: The experiment is subdivided into three parts, first is the determination of centripetal force with variable radius of rotation, determination of centripetal force with constant radius and variable mass of rotating body and determination of mass of rotating body with constant radius and variable force. In the first part of the experiment, we determine the centripetal force of the rotating body with a given radius. With the gained results, we observed that period increases as the radius increases. Consequently, frequency decreases as the radius increases. This implies that radius is directly proportional to period but inversely proportional to frequency. In the second part of the experiment, we determine the centripetal force with a constant radius and a given mass of rotating body. With the gathered results, we observed that the period increases as the mass of the rotating body increases but its frequency decreases. This implies that mass is directly proportional to period but inversely proportional to frequency. Lastly, the third part of the experiment, we determine the mass of the rotating body with constant radius and given force. From the gathered data, experimental values of the mass of rotating body is almost the same with the actual mass of rotating body having in mind that the centripetal forces vary. Also, as the centripetal forces vary, the frequency also varies and will cancel out the effect of varying the force. Therefore, it will not affect the value of the mass of the rotating body. Conclusion: Uniform circular motion can be described as the motion of an object in a circle at a constant speed. As an object moves in a circle, it is constantly changing its direction. At all instances, the object is moving tangent to the circle. In a uniform circular motion, there’s a force acting upon making it move in a circular manner which is the centripetal force. A centripetal force is a force that makes a body follow a curved path. Its direction is always orthogonal to the motion of the body and towards the fixed point of the instantaneous center of curvature of the path. Without a centripetal force, the object in motion will definitely move in a straight path. In a uniform circular motion, it may seem called as uniform motion for it doesn’t have an acceleration but it does have and that is centripetal acceleration. Centripetal Acceleration is the rate of change of tangential velocity. This acceleration always directed to the center of the curvature of the path.